Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It discloses that the answer is advisory and why, and states that it returns a per-dimension verdict quoting the limit. However, it does not describe behavior for partially provided dimensions or invalid waterway names, which is a minor gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences: purpose+source, output behavior, and caveat+alternative. It is concise, front-loaded, and every sentence adds value without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers what the tool does, what it returns (per-dimension verdict with limit), the advisory nature, and the alternative for journeys. No output schema exists, so the return description adequately covers that. For a simple query tool, the description is complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already describes each parameter. The description adds context that the tool checks all four dimensions and that they are from CRT published figures, but it does not add additional semantics beyond the schema's parameter descriptions. Baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses the specific verb 'Check' and clearly identifies the resource: 'boat dimensions against the published maximum craft dimensions for a named British waterway' (length, beam, draught and air draught). It further distinguishes itself from the sibling tools by explicitly recommending plan_route for whole journeys.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states when to use the tool (for a single named waterway) and when not to (for a whole journey, use plan_route instead). It also advises treating the answer as advisory due to varying draught and headroom, providing clear context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.